Tymofii O. Pathogenesis of disorders of the hypothalamic-epiphyseal interrelations induced by photoperiod changes

Object - restructuring subpopulations of neurons in the hypothalamic paraventricular nucleus of rats at different modifica-tion photoperiod; purpose - to determine the pathogenesis of stress-induced disorders morphometric, functional state of hypo-thalamic paraventricular nucleus of rats and gene expression changes in response with very early-fos, and the role of melatonin in the mechanisms of correction of deviations; methods - pathophysiological, immunohistochemical, immunofluorescence, morphometric, densitometric, histological, correlation and regression analysis, mathematical statistics; results – the study detects morphofunctional changes of the lateral large cellular and medial small cellular subnuclei of the paraventricular nuclei in the hypothalamus of rats under different length of light period; more marked circadian regularities in the rebuilding of morphofunc-tional parameters of the hypothalamic neurosecretory cells examined under fixed light than under light deprivation have been found; received concerning photo-induced disorders character of melatonin receptor density in paraventricular nuclei subnuclei of the hypothalamus with termination of daily variations in average tendencies, and with variation intensification of an individ-ual reaction of the animal hypothalamic structure to light stress; injection of exogenous melatonin (0,5 mg/kg) has been found to promote increasing resistance of the ultrastructures to light stress, improvement of area component indices of paraventricular nuclei neurons and RNA concentration in them; disorders of quick functional response gene expression c-fos and immunospecif-ic protein c-Fos, determined by it the corticoliberin-producing and vasopressin-synthetizing subnuclei of the hypothalamic para-ventricular nucleus in rats, have been demonstrated to be the indicator of early desynchronosis under light stress and light depri-vation.